chago996

GT1 engine case or 9A1?

micahbones

Still Mezger GT1 based engine in the 2011 GT2 RS.

80shilling

Yup... What He said.. ^^^^^^^ GT1 Metzger Block, running 1.4 Bar boost !!!

Larry Cable

I think it's going to be a while before any of the GT cars will abandon the Mezger engine ...

I wouldn't expect it until at least one of the race cars has 9A1 and demonstrates it's abilities to endure and deliver

TB993tt

Try 1.6 bar in the manifold, less as it enters the combustion chambers

80shilling

1.6 Bar?? The official literature stated 1.4 Bar.... At 1.6 Bar, there can't be much headroom left and how in the hell are they running 1.6 Bar on pump gas? Those tricky, smart German engineers,,

996FourEss

I thought the about to be released GT2 RS has a modified version of the new direct injection engine from the Turbo (ie. no cylinder liners, etc) and they were havign some problems in development in keeping the whole thing together. That is, it is not a development of the racing engines that are used in the GT3 / GT3 RS. I hope this information is wrong.

Apparently, the new engines, while technically very good are frowned upon by purist racers as the ability to strip them down and rebuild them is greatly reduced. Can someone in the know comment further here perhaps?

Riz

Is there a reason why they did not go with the 3.8L Metzger engine from the MY10 GT3 RS and turbo charge it? Is it due to the 3.6L Metzger engine from the 09 turbo/Gt2 being stronger because of the thicker block? Because the block is thicker, it is better able to withstand the extra stresses of turbocharging. Maybe someone with more knowledge can chime in. In any case, this proves that the 9A1 is just not as strong/reliable when it really counts as in a GT2/GT3, Cup Car!

Carrera GT

Thicker "block"? Perhaps you mean cylinder walls, which become thinner as bore becomes larger (assuming the same stroke for the given displacement.)

The stress is in the big end (main bearings) and in simply keeping the heads on the case at those boost levels -- they tend to stretch the head studs and then things go badly. : )

Anyway, in a turbo, it's all about heat. The 530 lb-ft +/- was about the nominal durable limit of the 993 Turbo, so I don't think the engine is by any means overstressed -- water cooled heads and no doubt fortified internals surely mean it will be very stout.

C.J. Ichiban

well if they had problems developing it then obviously they wouldn't be releasing it.

and... you don't really spend a lot of time tearing down and rebuilding with the new 997 engines as they're simply thrown away and swapped out for new ones when things go bad.

MJSpeed

WTF? This thread is a perfect example of how insane internet rumors start...

niche

Just saw this thread and had same question as OP. What is bs and what isn't? Curious.

TB993tt

The official literature I saw said 1.6 bar. The standard GT2 runs 1.4 bar.

My GT2 also runs 1.6 bar for similar power - what has to be appreciated is this boost pressure is needed to make the expansion manifold work, it is 1.6 bar max back pressure in the manifold but when the manifold allows the compressed air to expand (and cool) as it enters the combustion chambers the boost drops - the actual boost for the 620PS is probably around 1.2bar as it enters the combustion chambers - also remember the 997tt/GT2 runs slightly lower static compression ratio to the 996tt/GT2 (9:1 vs 9.4:1) which allows for higher boost numbers like for like.

The RS engine has improved intercoolers, plastic intake expansion manifold (for weight saving) and it will run bigger VTGs and maybe different cats, apart from that it is the same as the GT2 engine.

Alan Smithee

Of course it remains to be seen, but I have to think the GT3RS and GT2RS are the pinnacle of GT1 NA and turbocharged motor development, respectively.

It doesn't make sense that Porsche developed a new family of modern motors during their peak of profitability that would not be used throughout the range, especially with upcoming new emissions requirements both here and in the EU.

For those that lament the highest performing Porsche cars sharing motors with the more pedestrian models, remember that is the way it always was before the 996...

Larry Cable

True, but the R and the RSR now both sport a "4.0L" engine (3996) it's concievable that as the 997.2 engine followed the previous generation of race cars to a 3.8 that the next generation could go to a 4.0/3.9L and an incremental
+15 to 30bhp

Not sure about the 2's turbocharged engine ... can it go to 3.8L or beyond (does it even need too if FAI can deliver 620bhp)?

As with everything it depends on so many factors and decisions ...

consider this though, the next GT3 (if there is one) has to at least equal and probably better the current cars performance envelope.

While the 9A1/X51 (3.8L) engine is good, can it be made to match the Metzger GT1 block?

currently (in X51 form) it's shy about 27-42bhp

only time will tell - glad I got the last of the 'real' GT3's